Controllable variable inertia fluid heating and storage system

ABSTRACT

Controllable variable inertia water storage system for heating and/or cooling, comprising: a plurality of water storage volumes for storing and heating water, these being either a vessel comprising sub-volumes or independent multiple vessels, said volumes being interconnected in series; a water inlet and outlet connect to the interconnected volumes; an independent water heater and/or cooler for each volume. 
     Method for operating said system comprising: defining target sub-temperatures for each volume, wherein said target sub-temperatures are sequentially higher for each volume, in the direction of the water flow from inlet to outlet; increasing the target sub-temperatures in periods of forecasted higher demand, and, inversely, decreasing the target sub-temperatures in periods of forecasted lower demand; heating the volumes up to the target sub-temperatures, when the user indicates so or when a source of heat is available.

TECHNICAL FIELD

The present disclosure relates to water heating and storage systems, inparticular to a controllable variable inertia multiple volume orsegmented sub-volume system for water heating and storage.

SUMMARY

The disclosure comprises a controllable variable inertia water storagesystem for heating and/or cooling, comprising:

-   -   a plurality of water storage volumes for storing and heating        water, these being either a vessel comprising sub-volumes or        independent multiple vessels, said volumes being interconnected        in series;    -   a water inlet and outlet connect to the interconnected volumes;    -   an independent water heater and/or cooler for each volume.

In some embodiments, said independent water heater and/or cooler for avolume is a heat exchanger for exchanging heat with a fluid fed by aheat or cool source.

In some embodiments, two or more of said volumes comprise, as saidindependent water heater and/or cooler, heat exchangers for exchangingheat with fluid fed by the same source of heat or cool.

In some embodiments, said source of heat or cool is a boiler, thermalsolar panel, electric heater, combined heat and power cogeneration unit.

Some embodiments comprise further volumes which are not interconnectedwith said interconnected volumes, said further volumes comprisingindependent water inlet and outlet connections.

In some embodiments, said further volumes each comprises a water heaterand/or cooler that is independent from the water heaters and/or coolersof said interconnected volumes.

In some embodiments, said volumes are thermally insulated, in particularbetween said volumes.

In some embodiments, the volumes are arranged linearly or radially, inparticular concentrically.

In some embodiments, the serial interconnections between volumes arearranged such that water stratification by temperature is promoted.

In some embodiments, the serial interconnections between volumescomprise flow deflectors such that the disruption of waterstratification by temperature is minimized.

In an aspect, a method for operating the system as any one of the aboveand below described, comprises the steps of:

-   -   defining target sub-temperatures for each volume, wherein said        target sub-temperatures are sequentially higher for each volume,        in the direction of the water flow from inlet to outlet; and        wherein the target sub-temperature of the volume connected to        the outlet is the target temperature of the water to be        supplied;    -   increasing the target sub-temperatures in periods of forecasted        higher demand, and, inversely, decreasing the target        sub-temperatures in periods of forecasted lower demand;    -   heating the volumes up to the target sub-temperatures, when the        system user indicates so or when a predefined source of heat is        available.

Some embodiments comprise limiting the water temperature of each volumeby controlling the heating with user-defined minimum and maximumtemperature limits for each volume.

In some embodiments, the step of heating the volumes comprises firstheating up to a predefined number of volumes that are closest to thewater outlet; and sequentially heating up to a predefined number ofother volumes that are next closest to the outlet, until all volumesreach the target sub-temperatures.

In some embodiments, the step of heating the volumes comprises firstheating the volume that is closest to the water outlet; and sequentiallyheating the other volumes, one by one, that are next closest to theoutlet, until all volumes reach the target sub-temperatures.

In some embodiments, the step of heating the volumes comprises firstheating a predefined number of volumes that have the larger differencesbetween current temperature and target sub-temperature; and sequentiallyheating predefined number of volumes that then have the largerdifferences between current temperature and target sub-temperatures,until all volumes reach the target sub-temperatures.

In some embodiments, the target sub-temperatures are increased ordecreased according to the heat availability of the heat source.

In some embodiments, the system comprises a control module configured tooperate any of the above or below described methods of operation.

In some embodiments, the control module comprises data connections,local or remote, for providing information on the system status and forreceiving user configurations.

BRIEF DESCRIPTION OF DRAWINGS

The following figures provide preferred embodiments for illustrating thedescription and should not be seen as limiting the scope of invention.

FIG. 1—Schematic representation of systems and sub-systems of the vesselof embodiments hereby described.

FIG. 2 a—Schematic representation of integration of the mechanical andcontrol system of embodiments hereby described with linear layout with adomestic generic water heating system.

FIG. 2 b—Schematic representation of integration of the mechanical andcontrol system of embodiments hereby described with linear layout with adomestic generic water heating system using a natural gas boiler andelectric photo-voltaic cells.

FIG. 2 c—Schematic representation of integration of the mechanical andcontrol system of embodiments hereby described with linear layout with adomestic generic water heating system using solar panels and electricphoto-voltaic cells.

FIG. 2 d—Schematic representation of integration of the mechanical andcontrol system of embodiments with linear layout with a domestic genericwater heating system using a micro combined heat and power cogenerationunit (micro CHP).

FIG. 3 a—Schematic representation of an alternative embodiment whereinone of the sub-vessels is not interconnected.

FIG. 3 b—Schematic representation of an alternative embodiment whereinone of the sub-vessels is not interconnected and is heated/cooledindependently.

FIG. 4—Schematic representation of layouts of the vessel withsub-volumes.

FIG. 5—Schematic representation of decision tree of the control system,highlighting the capability to handle dynamic loads on the energyavailability and demands based in instantaneous or provisional data aswell as the possibility of choosing the energy source.

FIG. 6—Schematic representation of the operative control module.

FIG. 7—Schematic representation of the decision tree of the operativecontrol module.

Wherein in said figures the following elements are present:

-   -   1—external agent(s) (human or not)    -   2—hot water outlet (or inlet for cooling)    -   3—cold water inlet (or outlet for cooling)    -   4—thermal energy source    -   5—valve assembly (one or more valves to control the hydraulic        energy)    -   6—sub-volumes    -   7—energy exchange device for the thermal hydraulic energy source        (or sink for cooling)    -   8—energy exchange device for the electric energy source (or sink        for cooling) or other energy source    -   9—controller    -   10—bi-directional data link between vessel and an external        communication network    -   11—communication network    -   12—hydraulic actuators' signal    -   13—temperature sensor    -   14—micro cogeneration unit fuel    -   15—micro cogeneration unit, including required piping subsystems        and others not relevant for the disclosure    -   16—electricity produced by the cogeneration unit, photovoltaic        cells or other source    -   17—electricity for auto-consumption    -   18—electricity to supply or receive from the power grid    -   19—local external agent (human or not) (can be a home user, or        an automatic controller)    -   20—remote external agent(s) (human or not)    -   21—local communication network    -   22—other communication network    -   23—solar photovoltaic panel and control system    -   24—solar thermal panel and control system    -   25—boiler    -   26—insulation    -   27—energy being produced sensor (current and/or voltage based)    -   28—initialization procedures    -   29—machine status    -   30—communication procedures    -   31—is energy being supplied?    -   32—want to force the vessel to heat?    -   33—energize with how much energy?    -   34—how to energize?    -   35—use which energy source?    -   36—energize which sub-volume?    -   37—is none available?    -   38—energize sub-volume with defined energy source    -   39—vessel is already fully energized

DETAILED DESCRIPTION

The necessity to efficiently store and manage energy is a fundamentalchallenge to modern human life. The technology described in thisdocument addresses this challenge allowing a more effective way tomanage this energy not only in a transient load/unload state of thesystem but also in a stationary regime of usage. The new constructiontechnology is enhanced by using advanced control systems, that will alsobe described in this document, and that allows to integrate differentenergy sources to collaboratively heat, or cool, the contents of avessel in a cooperative way. These energy sources can be, for example,electricity, natural gas, biomass, pellets, among others. The vesselcontrol system has a two-way communication mechanism such that it allowsthe exchange of information between the machine and an external agent.

In this document we will consider, for illustration purposes only, thatthe vessel is inserted in a standard domestic hot-water system usingsolar panels as the primal heat source. Other uses, e.g. industrial orcommercial, may be contemplated.

Vessel or tank may be used interchangeably in the present disclosure,considering that the disclosure is straightforward to apply to bothpressurized and unpressurized vessels.

This system comprises a primary fluid circuit that transports thermalenergy from, for example, the solar panels to the hot water vessel. Thistechnology can be applied to any other system where the user wishes tostore thermal energy. This includes several other systems to heat orcool the inertial fluid not described in this document but which areknown in the technical field.

The vessel is connected to one or more energy sources that heat thewater in the vessel in a collaborative way, in the case considered,thermal energy and electric energy. This setup can be materialized forexample by connecting the vessel to solar panels and photo-voltaiccells, or a micro combined heat and power boiler, or directly to themain power grid, among others.

The technology described can be used wherever one wishes to storethermal energy. To do so, and in the example taken for illustrationpurposes, the vessel is composed by smaller sub-volumes whose heating isdone independently using both electric resistances andthermodynamic-hydraulic heat exchanger coils.

One of the main concepts consists of a disruptive solution withtechnology used by manufacturers of such vessels, increasing its addedvalue and differentiation in comparison to other vessel technologies.This new innovation allows the vessel to:

-   -   1. In specific conditions, to supply hot water during more time        due to the compartmentalization of the vessel and the careful        choice of what volume to heat in each instant;    -   2. Have a bigger volume without the added loss of efficiency.        Since the sub-volumes closest to the outlet have small        dimensions, they can be heated in a short time. The other        sub-volumes store extra energy beyond the minimum required        energy for instantaneous use. This way, the system can function        efficiently with low quality heat sources and can store more        energy than a conventional vessel in the same conditions;    -   3. Reduce complexity by avoiding usage of layouts for example        fluid deflectors used in prior art vessels to promote liquid        stratification;    -   4. Store energy more efficiently in situations of lower solar        radiation when connected to solar panels or photo-voltaic cells.        This occur in countries with high latitudes like Germany and the        United Kingdom;    -   5. Interact with different energy sources heating each        sub-volume independently with a multitude of heating systems,        such as electric resistances and thermodynamic-hydraulic coils,        among others;    -   6. Choose the energy source to use in each instant by a control        system that can use electric and hydraulic valves;    -   7. Interact with the user and other external entities with        interest in participate directly or indirectly in the way the        vessel operates and choose the energy source. This is done by        the vessel controller or by other remote access connection;    -   8. Reduce transients in the operation of others systems that        produce energy that are responsible for a loss in the efficiency        of such systems. Being able to store a large amount of energy,        the vessel can be a strategical energy buffer, increasingly        storing energy from intermittent energy sources, like wind        turbines and combined heat and power co-generation units.

The vessel hereby proposed according to some embodiments shares the samevolume and shell common to other existing products in the market. Themost differentiating aspects are:

-   -   1. Holistic energy transfer system control. These energy        transfer systems are thermodynamic-hydraulic heat exchanger        coils and electric resistances which are installed each in one        or more vessel sub-volumes;    -   2. Vessel volume division, creating one or more independent        sub-volumes that are connected between each other. This is done        by associating smaller volume vessels in a single equipment or        by placing internal divisions, which might be thermally        isolated, inside a single larger vessel. The connections may be        controllable, i.e., switchable between open and closed states.        Other non-interconnected volumes may also be associated with the        system.    -   3. Integrated and intelligent vessel control system that chooses        the heat source based in information that can be from within or        outside of the vessel. This control actuates valves and        electrical switches so that the chosen heat source is used.    -   4. Connection of the vessel control system to information        networks and domotics with active control functionalities so        that external agents can influence the operation of the vessel.    -   5. Compactness of the vessel system by integrating all        sub-vessels, the control system and the heat transfer systems in        a small package.

The embodiments hereby described comprise of a vessel to store a fluid.Applied to solar hot-water systems it addresses several problems thatexist in the standard arrangement of such systems. The maincharacteristics of this new vessel technology are:

-   -   1. Optimized heating, or cooling, of a liquid;    -   2. Advanced control of the heating, or cooling, system;    -   3. Communication between the vessel and an external agent (human        or not human) to the system.

Using a solar hot-water and/or photo-voltaic system for illustrationpurposes allows us to identify and present several characteristics ofthe new vessel technology:

We can identify 3 problems in solar hot-water conventional systems:

-   -   1. In his daily life, a user knows that if he consumes the hot        water from the vessel in the end of the afternoon, he might have        no hot-water heated with the solar panels to use in the morning        because the system will need time to re-heat the vessel with the        morning sun. Therefore, he will need to change his routines and        habits in order to take full advantage of the solar energy by        planning the number, quantity and time of his hot water        consumptions.    -   2. As referred in the last item, heating the overall volume of a        water vessel is very time-consuming. This is dependent on the        volume of the vessel. A smaller vessel heats faster. However,        has a lower hot-water “availability” since when hot water is        removed from the vessel it is replenished with cold water from        the main line, lowering the water temperature in the overall        vessel. This way, the volume of available hot water to the user        is different than the real volume of the vessel. This depends on        several variables like water flow-rate as well as inlet and        outlet water temperature.    -   3. To solve the problems identified in the last items, we can be        led to match bigger solar panels to vessels of smaller        dimensions. In real working conditions, when the water in the        vessel reaches a pre-determined temperature (between 70 to 90°        C.), the circulation pump of the primary circuit halts so that        the water in the vessel is not vaporized and so that the        hydraulic equipments (valves, pumps, . . . ) are not damaged.        After stopping, the circulation pump of the primary circuit will        only be turned on after the primary circuit fluid lowers from a        pre-determined value. In real working conditions it will only        occur after sunset. By stopping the primary circuit it will        continue to increase its temperature reaching very high        temperatures and in specific occasions it can vaporize. This        occurs when the hot water consumption is insufficient to drain        the excess energy captured by the solar panels and it represents        a waste of the solar energy captured that in extreme cases can        even damage the solar panels and the primary circuit piping and        fittings.

The new vessel under development addresses these issues by a systemcomprising a hot water storage vessel divided in an array of sub-volumesof smaller dimensions. By selectively, and according to methods of thedisclosure, heating each of these sub-volumes, it is possible to controlthe quantity of water being heated and so, change the inertia mass offluid being heated in each instant.

By changing the water quantity being heated in each instant, it ispossible to make available a specified volume of water in shorter timethan conventional systems and increasing the hot-water “availability” ofthe system. This way we reduce the burden of changing routines andhabits for the end user of the hot-water.

This technology also enables to oversize the vessel for a specificheating system such that the situations mentioned in item 3) do notoccur. With the current state-of-the-art technology oversizing thevessel increases the problems of items 1) and 2).

Improvements:

-   -   1. Less time to heat a usable volume of water.    -   2. It is possible to increase the overall vessel volume without        compromising the time taken to heat the water in the vessel.    -   3. Efficient usage of low power and intermittent energy sources.

To create new ways to use a hot water vessel:

-   -   1. Use of the vessel as an energy reservoir which uses the most        convenient energy source in each instant.    -   2. Use of the energy reservoir by the user or other external        entities or agents with different goals in sight, like, for        example, to balance energy grids (of electricity, natural gas, .        . . ), lowering heating costs, . . . .

The technology described comprises a water storage vessel composed by anarray of smaller volumes arranged in a compact size or by subdividing alarger volume into smaller fractions by placing thermal insulated wallsinside the vessel. Each sub-volume has independent heating elements(heating coils and electric resistances) that are holistically andindependently controlled. By actuating in valves and the electroniccircuits that control the heating coils and electric resistances of eachsub-volume, it is possible to control the quantity of water being heatedin each instant and so, vary the inertia of the system being heated.

Using this technology, a volume of water is heated in a fraction of thetime required by conventional systems, increasing the usable/availablehot water volume of a vessel and reducing the burden and behavioralchanges imposed on users of solar hot water systems in order to takefully advantage of such systems. By carefully choosing the dimension ofeach sub-volume, this technology enables to use a vessel of biggercapacity increasing the energy storage capacity of the overall system.

The machine comprises the integration of two different systems: amechanical system and a control system that controls and interfaces themachine with the external environment (cf. FIG. 1).

The mechanical system comprises a sub-system of inertial liquid storageand another sub-system for energy transfer. The first consists ofseveral water storing vessels integrated, or not, see as mentionedabove, in a single compact equipment. The second sub-system consists ofseveral actuators and energy transfer equipments (e.g. valves, heatexchangers, electric resistances, . . . ) to enable the energy transferinto the vessel and each sub-volume of the first sub-system. Theseenergy transfer equipments can be located inside or outside of eachsub-vessel.

The choice of the sub-volume to heat and the energy transfer mechanismto use is decided by a control system that actuates valves and/orelectronic circuits.

The control system consists of electronic control devices that, based onexternal and internal inputs, control the way the mechanical systemoperates.

The control system chooses in each instant which sub-volume to heat andwith which energy source using information from local sensors placed inthe vessel and information acquired from communication networks withexternal entities (sensors, operators, servers, machines, . . . ) thatcan interact with the vessel and influence its operation.

These decisions (which sub-volume to heat and with which energy source)are based on intelligent algorithms that take into account theinstantaneous balance of energy demanded from and supplied to the vesselas well as historical data to predict the future trend of these energyparcels and optimize the overall system performance.

The control system can interact with services facilitated by otherentities, namely “cloud based services” or other proprietary servicesand networks. The capability to communicate in small or large scalenetworks enable new advanced features. When integrated in a domoticssystem, the vessel can communicate with other equipments such as outsidemeteorological devices as well as work together with other house heatingdevices and other appliances.

When connected to the Internet, the system can take advantage of“cloud-based” M2M (Machine-to-Machine) services. Examples of possiblefeatures are usage data collection for service providers and end-users,firmware upgrades, integration with intelligent grid management systems,etc. . . .

The control system can be developed as integrated part of the vessel oras an external add-on to the vessel allowing it to have the functionsdescribed.

In terms of the mechanical system, the vessel of the embodiments herebydescribed stores thermal energy dynamically, adapting the quantity offluid to heat, or cool, to the heating, or cooling, power beingdelivered to the machine by the heat exchanging circuits, the userenergy demands as well as external inputs.

By incorporating an intelligent control that will be presented below,the heat exchangers on the corresponding smaller sub-volume aretriggered. By heating, or cooling, smaller sub-volumes the instantaneoustemperature change rate is increased in that sub-volume leading to afaster heating of the water that is available to the user.

These smaller sub-volumes are connected between each other in such a wayto promote a continuous discrete pre-heating, or pre-cooling, from theintake of the fluid to be heated, or cooled, to the outlet of thevessel. This is possible by connecting the hot-pipe of a sub-volume tothe cold-pipe of the adjacent sub-volume.

The layout of the connections between sub-volumes was thought such thatit promotes stratification in each sub-volume. The linear arrangement ofthe sub-volumes can be seen as a way to impose discrete forcedstratification in the vessel.

In terms of the control system, the operation of the control module isshown in FIG. 6. The main purpose of this module is to determine whichsub-volume to heat, or cool, and with which energy source. In order todo so, it relies on instantaneous as well as provisional computed databased on the history of energy consumption, energy availability andother data pertinent for its operation (for example, meteorologicalforecasts, user or external agents needs and preferences, etc. . . . ).

The control system is designed to answer three simple questions:

-   -   1. How to heat, or cool, the vessel?    -   2. Which energy source shall be used?    -   3. Which sub-volume should be energized?

FIG. 7 shows how the decision tree is arranged in order to answer theprevious questions.

After an general initialization procedure (28), the control systeminteracts with the sensor groups (13) and (27) to acquire informationregarding the instantaneous system status, including controls via a userinterface.

The communication procedures (30) that follow manages the dialog betweenthe vessel control system and other external agents (1), (19) and (20).This is done using a general communication network (10), (21) and (22).This interaction allows the control system to communicate its currentstatus as well as other computed and sensed quantities, and also toreceive information affecting its operation. Such information caninclude, among other things, meteorological actual readings andforecasts, overriding commands, maintenance instructions and firmwareupdates or upgrades, . . . ).

With this information, two parallel lines of decision leading to twodifferent questions arise (31) and (32). If a agent (1), (19) or (20)has asked the vessel to heat with a determined amount of energy and/orpower and/or source at a specific time and/or time interval (32), thevessel will compute the heating power required and perform such action(34-39). On the other hand of the parallel branch, if there is energybeing delivered to the vessel (31), the control system will also act insuch a way to store that energy accordingly (34-39).

The question of how to energize the vessel (34) defines set-pointtemperatures in each sub-volume. These are the target temperatures toreach in each sub-vessel. By increasing the target temperatures eachsub-vessel is capable of increasing its energy storage capacity. This isparticularly important in the sub-volume closer to the outlet and in asituation when hot water is being consumed from the vessel.

On the other hand, a lower target temperature lowers the energy storagecapacity which is particularly important to reduce the thermal lossesfrom the vessel. The target temperatures are defined based on historicaland provisional data pertaining to energy demanded from and energysupplied to the vessel. When no energy demands are forecast in a nearfuture, the vessel operates with lower target temperatures.

This target temperature increases gradually each time the vessel becomesfully energized up to the maximum operational temperature of the vessel.When a demand is forecast, the vessel energizes increasing its targettemperatures. In this case the sub-volumes closer to the outlet willexperience a bigger increase in target temperature, and in such a waythat before the estimated demand time starts, there is enough energy inthe sub-volumes closer to the outlet to supply it. This mode ofoperation is herewith called ECO MODE.

The user, or agent, ((1), (19), (20)) is free to opt-out of thisprocedure (ECO MODE) or to limit the automatic calculation of targettemperatures by defining minimum and maximum limits for the targettemperatures and for each sub-volume. This new mode of operation isherewith called POWER MODE.

The decision of which energy source to use (35) is based onavailability, demand and user, or agent ((1), (19), (20)), preferences.The availability and demand are accessed by the sensor groups (13) and(27). The user, or agent, preferences are known from the user interfaceas well as from the communication connection described (10), (21) and(22).

The decision of which sub-volume to energize (36) is based on the targettemperatures defined for each sub-volume. The sub-volume closer to anoutlet will be energized first until it reaches its target temperature.Then, the adjacent sub-volume will be energized and so on until the lastsub-volume is fully energized. Note that, in ECO MODE, each time thevessel is fully energized, the target temperatures are increased. Thisprocedure continues until the maximum operating temperature for thevessel is reached.

Following FIG. 7, and having answered all questions, the control moduleperforms the required actions, energizing the system (38).

The control system has an interface that permits several levels ofinteraction:

-   -   1. Domotics network integration—by interacting with other        devices inside the house (using technologies such as KNX, or        others) allows extending the reach of the vessel energy        monitoring and control, optimizing its operation. It is also        possible to control and monitor the vessel by using other        domotics integrated components from the house.        -   With the domotics network integration it is possible to            collect data such as inside and outside house temperature,            occupancy, and other occupants habits, . . . and adjust the            behavior of the vessel accordingly, i.e. adjusting to            weather, occupancy, etc. . . . as described in the operation            of the ECO MODE of operation and the “How to energize the            vessel?”question.    -   2. Interaction with other energy systems, collaborating in the        same task of energy management in such a way to decide which is        the best energy source/system to use to heat the vessel. For        example, natural gas boiler, solar thermal system, electric        resistances, . . . .    -   3. The integration with a communication network, for example the        internet e.g. world wide web (WWW), allows to access a global        level of information, exterior to the vessel and the house where        it is installed in like actual and provisional meteorology as        well as other data relevant to its operation.    -   4. The integration with an external communication network allows        the vessel to interact with a centralized system that can        retrieve history energy consumption patterns, diagnose        malfunctions and perform maintenance procedures remotely as well        as interact and condition the operating procedure of the vessel        by interacting in the decision of the energy to use and when to        use it, etc. . . .    -   5. Interaction with energy production equipments that see        advantages in using the energy storage/buffer characteristics of        the vessel of the embodiments hereby described. For example, to        reduce transients in the operation of micro-CHP (combined heat        and power boilers) and other energy producing equipment.    -   6. Use of the electrical energy produced by co-generation        boilers and micro co-generation boilers, photo-voltaic cells,        and/or other electricity producing systems to heat the water in        the vessel. This way, the heating speed is increased and the        auto-consumption of the produced electric energy is promoted.

In terms of construction, the vessel is composed of several sub-volumes.By integrating each smaller sub-volume in a single vessel the system ismore compact. Each sub-volume has independent heat exchangers thatpromote the energy exchange between the primary circuit and the fluidthat is inside the vessel.

The sub-volumes can be, in a preferred embodiment, radially or linearlyarranged, as shown in FIG. 4. The radial topology is thermodynamicallymore efficient since the surface between each sub-volume and the outsideis minimized. This topology is characterized by large heat transfersurfaces between each sub-vessel level. These levels are arranged with adecreasing temperature with the radial distance to the center. Since themost external sub-volume is at a lower temperature, the heat losses areminimized. In the radial layout, the connections between each sub-volumeare more complex to design and the overall vessel is more complex tobuild. The radial construction does not require 360°—embodiments may befully concentrical or only partially so, arranged as radial ‘sectors’.

The linear arrangement is not as thermal efficient as the radialarrangement. However, it allows a faster, simpler and more economicalconstruction and maintenance.

Each sub-volume has one or more energy transfer systems which can belocated inside or outside each sub-volume. These energy transfer systemscan be connected to other equipments that supply energy to the vessel.For example, boilers, solar panels, photo-voltaic cells, co-generationor micro co-generation boilers, . . . .

Embodiments may comprise one or more interconnected sub-volumes, oroptionally some additional not interconnected sub-volumes, of smalldimensions with independent energy exchanger mechanisms and integratedcontrol.

In some embodiments each sub-vessel is insulated from the othersub-vessels.

Embodiments may comprise integrated connection of sub-volumes of reducedcapacity with the purpose of storing energy for domestic or industrialapplications.

In some embodiments each sub-volume may have one or more system forenergy transfer independently and holistically controlled.

In some embodiments the energy exchanger mechanisms can be hydraulic,electric or using other technology.

Embodiments may comprise integrated radial or linear sub-vessels;

Embodiments may comprise radial volume system layout as a way to promoteefficiency, simplicity, more economic construction and maintenance, andsystem compactness.

Embodiments may comprise intelligent system control with forecast of theenergy supply as well as user energy demands;

Embodiments may comprise connection of the vessel to informationnetworks, as domotics domestic, industrial or others;

Embodiments may comprise connection of the vessel to communicationnetworks as a way to access generic and relevant decision supportinformation for the optimization of the operation of the vessel;

Embodiments may comprise connection of the vessel to communicationnetworks as a way to interact with other services such as monitoring,control, diagnostic and maintenance services.

Embodiments may comprise choosing in each moment the energy source toheat, or cool, the vessel contents by an appropriate control andcommunication strategy.

Embodiments may comprise communication between the vessel and differentthermal and electric energy producing equipments (such as boilers, solarpanels, photo-voltaic cells, electric resistances, co-generation andco-generation boilers, . . . ).

Embodiments may comprise control system as an integrated module or anexternal add-on module to the vessel.

It is to be noted that the energy exchanger is configured in the presentfigures for co-current or parallel flow, but counter-current flow isalso an alternative.

The disclosure is reversible in terms of cold or hot operation. Forexample, for cold operation, the volume closest to the outlet will bethe volume with the lowest target sub-temperature. Water is disclosed asan exemplary fluid, but other liquid fluids may be used forheating/cooling in the system. The volumes being interconnected inseries means that the volumes are connected in a ‘daisy-chain’ or wherethe output of a precedent volume is connected to the output of asubsequent volume.

The above described embodiments can be combined.

The following dependent claims set out particular embodiments of theinvention.

1. A controllable variable inertia water storage system for heatingand/or cooling, comprising: a. a plurality of water storage volumes forstoring and heating water, these being either a vessel comprisingsub-volumes or independent multiple vessels, said volumes beinginterconnected in series; b. a water inlet and outlet connect to theinterconnected volumes; c. an independent water heater and/or cooler foreach volume; d. a control module configured to operate the method of anyof the claims 18-22. wherein the control module comprises dataconnections, local or remote: a. for providing information on the systemstatus and for receiving user configurations; and/or b. for exchangingheat availability with heat source devices; wherein the data connectionsare one or more of domotics data connection, machine-to-machine—M2M—dataconnection, service providers' data connection, and/or energy providers'data connection.
 2. The system according to claim 1, wherein saidindependent water heater and/or cooler for a volume is a heat exchangerfor exchanging heat with a fluid fed by a heat or cool source.
 3. Thesystem according to claim 2, wherein two or more of said volumescomprise, as said independent water heater and/or cooler, heatexchangers for exchanging heat with fluid fed by the same source of heator cool.
 4. The system according to claim 1, wherein said source of heator cool is a boiler, thermal solar panel, electric heater, combined heatand power cogeneration unit.
 5. The system according to claim 1comprising further volumes which are not interconnected with saidinterconnected volumes, said further volumes comprising independentwater inlet and outlet connections.
 6. The system according to claim 1,wherein said further volumes each comprises a water heater and/or coolerthat is independent from the water heaters and/or coolers of saidinterconnected volumes.
 7. The system according to claim 1, wherein saidvolumes are thermally insulated, in particular between said volumes. 8.The system according to claim 1, wherein the volumes are arrangedlinearly or radially, in particular concentrically.
 9. The systemaccording to claim 1 further comprising one or more additionalindependent water heaters and/or coolers for each volume.
 10. The systemaccording to claim 1, wherein the serial interconnections betweenvolumes are arranged such that water stratification by temperature ispromoted.
 11. The system according to claim 1, wherein the serialinterconnections between volumes comprise flow deflectors such that thedisruption of water stratification by temperature is minimized.
 12. Thesystem according to claim 1, wherein the control system can interactwith services facilitated by other entities, namely “cloud basedservices” or other proprietary services and networks, such that whenintegrated in a domotics system, the vessel can communicate with otherequipments such as outside meteorological devices as well as worktogether with other house heating devices and other/appliances.
 13. Thesystem according to claim 1 adapted for connection to the Internet sothat the system can take advantage of “cloud-based” M2MMachine-to-Machine service, in particular usage data collection forservice providers and end-users, firmware upgrades, integration withintelligent grid management systems.
 14. The system according to claim1, wherein the control system is an integrated part of the vessel or asan external add-on to the vessel.
 15. The system according to claim 1,wherein the control system is configured to determine which sub-volumeto heat, or cool, and with which energy source, by relying oninstantaneous as well as provisional computed data based on the historyof energy consumption, energy availability and other data pertinent forits operation, in particular for example, meteorological forecasts, useror external agents needs and preferences.
 16. The system according toclaim 1, wherein the control system is configured to determine energysource to use based on availability, demand and user, or agentpreferences, wherein the availability and demand are accessed by thesensor groups and the user, or agent, preferences are known from theuser interface as well as from the communication connection described.17. The system according to claim 1, wherein the control system isconfigured to: a. by interacting with other devices inside the house,extend the reach of the vessel energy monitoring and control, optimizingits operation; also to control and monitor the vessel by using otherdomotics integrated components from the house; b. by communicating witha domotics network, collect data such as inside and outside housetemperature, occupancy, and other occupants habits and adjusting thebehavior of the vessel accordingly, i.e. adjusting to weather,occupancy; c. by communicating with other energy systems, cooperate inenergy management in such a way to decide which is the best energysource and/or system to use to heat the vessel; d. connect with acommunication network, for example the internet e.g. world wide web(WWW), to allow access to information, exterior to the vessel and thehouse where it is installed, in particular actual and provisionalmeteorology; e. integrate with an external communication networkallowing the vessel to interact with a centralized system that canretrieve history energy consumption patterns, diagnose malfunctions andperform maintenance procedures remotely as well as interact andcondition the operating procedure of the vessel by interacting with thecontrol system; f. interact with energy production equipments tocomplement the characteristics of the vessel, in particular to reducetransients in the operation of micro-CHP (combined heat and powerboilers) and/or other energy producing equipment. g. use the electricalenergy produced by co-generation boilers and micro cogeneration boilers,photo-voltaic cells, and/or other electricity producing systems tofurther heat the water in the vessel.
 18. A method for heating and/orcooling water utilizing the system of claim 1 comprising the steps of:a. defining target sub-temperatures for each volume, wherein said targetsub-temperatures are sequentially higher for each volume, in thedirection of the water flow from inlet to outlet; and wherein the targetsub-temperature of the volume connected to the outlet is the targettemperature of the water to be supplied; b. increasing, the targetsub-temperatures in predefined periods or periods of forecasted higherdemand, and, inversely, decreasing the target sub-temperatures in otherpredefined periods or periods of forecasted lower demand; c. heating thevolumes up to the target sub-temperatures, when the system userindicates so or when a predefined source of heat is available.
 19. Themethod according to claim 18 further comprising limiting the watertemperature of each volume by controlling the heating with user-definedminimum and maximum temperature limits for each volume.
 20. The methodaccording to claim 18, wherein the step b) of heating the volumescomprises first heating up to a predefined number of volumes that areclosest to the water outlet; and sequentially heating up to a predefinednumber of other volumes that are next closest to the outlet, until allvolumes reach the target sub-temperatures.
 21. The method according tothe previous claim 20, wherein the step b) of heating the volumescomprises first heating the volume that is closest to the water outlet;and sequentially heating the other volumes, one by one, that are nextclosest to the outlet, until all volumes reach the targetsub-temperatures.
 22. The method according to claim 18, wherein the stepb) of heating the volumes comprises first heating a predefined number ofvolumes that have the larger differences between current temperature andtarget sub-temperature; and sequentially heating predefined number ofvolumes that then have the larger differences between currenttemperature and target sub-temperatures, until all volumes reach thetarget sub-temperatures.